thrash

thrash /vi./ To move wildly or violently, without
accomplishing anything useful. Paging or swapping systems that are
overloaded waste most of their time moving data into and out of
core (rather than performing useful computation) and are therefore
said to thrash. Someone who keeps changing his mind (esp. about
what to work on next) is said to be thrashing. A person
frantically trying to execute too many tasks at once (and not
spending enough time on any single task) may also be described as
thrashing. Compare multitask.